Light emitting device

ABSTRACT

Disclosed is a light emitting device including: a light emitting structure including a plurality of light emitting regions including a first semiconductor layer, an active layer and a second semiconductor layer; a first electrode unit disposed on the first semiconductor layer in one of the light emitting regions; a second electrode unit disposed on the second semiconductor layer in another of the light emitting regions; an intermediate pad disposed on the second semiconductor layer in at least still another of the light emitting regions; and at least one connection electrode to sequentially connect the light emitting regions in series, wherein the light emitting regions connected in series are divided into 1 st  to i th  light emitting region groups and areas of light emitting regions that belong to different groups are different (where 1&lt;i≦j, each of i and j is a natural number, and j is a last light emitting region group).

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority under 35 U.S.C. §119 to Korean PatentApplication No. 10-2011-0109757, filed in Korea on 26 Oct. 2011, whichis hereby incorporated in its entirety by reference as if fully setforth herein.

TECHNICAL FIELD

Embodiments relate to a light emitting device, a light emitting devicepackage, a lighting apparatus, and a display apparatus.

BACKGROUND

Red, green and blue light emitting diodes (LED) capable of realizinghigh luminance and white light were developed, based on development ofmetal organic chemical vapor deposition and molecular beam growth ofgallium nitride (GaN).

Such LEDs do not contain environmentally harmful substances such asmercury (Hg) used in conventional lighting apparatuses such asincandescent lamps or fluorescent lamps and thus advantageously havesuperior eco-friendliness, long lifespan and low power consumption, thusbeing used as alternatives of conventional light sources. The keyfactors in competitiveness of such LEDs are to realize high luminance,based on chips with high efficiency and high power and packagingtechnologies.

In order to realize high luminance, an increase in light extractionefficiency is important. A variety of methods using flip-chipstructures, surface texturing, patterned sapphire substrates (PSSs),photonic crystal techniques, anti-reflective layer structures and thelike are being researched in order to increase light extractionefficiency.

In general, a light emitting device may include a light emittingstructure to generate light, a first electrode and a second electrode toreceive power, a current blocking layer to disperse current, an ohmiclayer that ohmic-contacts the light emitting structure, and a reflectivelayer to improve light extraction efficiency. The structure of a generallight emitting device is disclosed in Korean Patent Laid-open No.10-2011-0041270.

SUMMARY

Embodiments provide a light emitting device to improve reliability andefficiency and control an area of light emitting regions according tothe intended purpose.

In one embodiment, a light emitting device includes: a light emittingstructure including a plurality of light emitting regions including afirst semiconductor layer, an active layer and a second semiconductorlayer; a first electrode unit disposed on the first semiconductor layerin one of the light emitting regions; a second electrode unit disposedon the second semiconductor layer in another of the light emittingregions; an intermediate pad disposed on the second semiconductor layerin at least still another of the light emitting regions; and at leastone connection electrode to sequentially connect the light emittingregions in series, wherein the light emitting regions connected inseries are divided into 1^(st) to i^(th) light emitting region groupsand areas of light emitting regions that belong to different groups aredifferent (where 1<i≦j, each of i and j is a natural number, and j is alast light emitting region group).

In another embodiment, a light emitting structure includes: a pluralityof light emitting regions including a first semiconductor layer, anactive layer and a second semiconductor layer; a first electrode unitdisposed on the first semiconductor layer in one of the light emittingregions; a second electrode unit disposed on the second semiconductorlayer in another of the light emitting regions; an intermediate paddisposed on the first semiconductor layer in at least still another ofthe light emitting regions; and at least one connection electrode tosequentially connect the light emitting regions in series, wherein thelight emitting regions connected in series are divided into 1^(st) toi^(th) light emitting region groups and areas of light emitting regionsthat belong to different groups are different (where 1<i≦j, each of iand j is a natural number, and j is a last light emitting region group).

The first electrode unit may be disposed on the first semiconductorlayer in the first light emitting region among light emitting regionsthat belong to the 1^(st) group. The second electrode unit may bedisposed on the second semiconductor layer in the last light emittingregion among light emitting regions that belong to the j^(th) group.

The first electrode unit may be disposed on the first semiconductorlayer in the last light emitting region among light emitting regionsthat belong to the j^(th) group. The second electrode unit may bedisposed on the second semiconductor layer in the first light emittingregion among light emitting regions that belong to the 1^(st) group.Areas of light emitting regions that belong to the same group may beidentical. At least one of a transverse length and a longitudinal lengthof light emitting regions that belong to different groups may bedifferent. An area of a light emitting region that belongs to ani−1^(th) group may be larger than an area of a light emitting regionthat belongs to an i^(th) group. Areas of light emitting regions thatbelong to respective groups may decrease from the 1^(st) group to thej^(th) group in order. One of a transverse length and a longitudinallength of the light emitting region may decrease.

The intermediate pad may be disposed on the second semiconductor layerin the last light emitting region among light emitting regions thatbelong to at least one of groups other than the j^(th) group. Theintermediate pad may be disposed on the first semiconductor layer in thelast light emitting region among light emitting regions that belong toat least one of groups other than the j^(th) group.

Each of the first electrode unit and the second electrode unit mayinclude a pad that receives power.

The intermediate pad may be electrically connected or may be notelectrically connected to the connection electrode in the same lightemitting region.

The light emitting device may further include: an insulating layerdisposed in the light emitting regions, wherein the connection electrodeis disposed on the insulating layer.

The connection electrode may include a first portion that passes throughthe insulating layer and contacts the first semiconductor layer in oneof adjacent light emitting regions.

The connection electrode may further include a second portion thatpasses through the insulating layer, the second semiconductor layer andthe active layer, and contacts the second semiconductor layer in theother of the adjacent light emitting regions, wherein the insulatinglayer is disposed between the second portion and the secondsemiconductor layer, and between the second portion and the activelayer.

The light emitting device may further include: a substrate disposedunder the light emitting structure; and a conductive layer disposedbetween the light emitting region and the insulating layer.

In another embodiment, a light emitting device includes: a lightemitting structure including a plurality of light emitting regionsincluding a first semiconductor layer, an active layer and a secondsemiconductor layer; a plurality of metal layers disposed under thesecond semiconductor layers in the respective light emitting regions; afirst electrode unit disposed on the first semiconductor layer in one ofthe light emitting regions; a second electrode unit electricallyconnected to the metal layer disposed under the second semiconductorlayer in another of the light emitting regions; an intermediate paddisposed on the first semiconductor layer in at least still another ofthe light emitting regions; and an insulating layer to electricallyinsulate the metal layers from each other, wherein the light emittingregions connected in series are divided into 1^(st) to i^(th) lightemitting region groups and areas of light emitting regions that belongto different groups are different (where 1<i≦j, each of i and j is anatural number, and j is a last light emitting region group).

The second electrode unit may be connected to the metal layer in thefirst light emitting region among light emitting regions that belong tothe 1^(st) group. The first electrode unit may be disposed on the firstsemiconductor layer in the last light emitting region among lightemitting regions that belong to the j^(th) group.

Areas of light emitting regions that belong to the same group may beidentical. An area of a light emitting region that belongs to ani−1^(th) group may be larger than an area of a light emitting regionthat belongs to an i^(th) group. Areas of light emitting regions thatbelong to respective groups may decrease from the 1^(st) group to thej^(th) group in order.

The intermediate pad may be disposed on the first semiconductor layer inthe last light emitting region among light emitting regions that belongto at least one of groups other than the j^(th) group.

Each metal layer may include at least one of an ohmic layer and areflective layer.

The light emitting device may further include a passivation layerdisposed in the light emitting regions, wherein the connection electrodeis disposed on the passivation layer.

The second electrode unit may include: a barrier layer electricallyconnected to the metal layer disposed in the another of the lightemitting regions; and a support layer disposed under the barrier layer.

The connection electrode may include: at least one first portion thatpasses through the passivation layer, the first semiconductor layer andthe active layer, and contacts the second semiconductor layer in one ofadjacent light emitting regions; and at least one second portion thatpasses through the passivation layer and contacts the firstsemiconductor layer in the other of the adjacent light emitting regions,wherein the passivation layer is disposed between the first portion andthe first semiconductor layer, and between the first portion and theactive layer.

The insulating layer may electrically insulate metal layers other thanthe metal layer electrically connected to the second electrode unit,from the second electrode unit.

BRIEF DESCRIPTION OF THE DRAWINGS

Arrangements and embodiments may be described in detail with referenceto the following drawings in which like reference numerals refer to likeelements and wherein:

FIG. 1 is a plan view illustrating a light emitting device according toa first embodiment;

FIG. 2 is a sectional view taken along a direction of AA′ of the lightemitting device illustrated in FIG. 1;

FIG. 3 is a sectional view taken along a direction of BB′ of the lightemitting device illustrated in FIG. 1;

FIG. 4 is a circuit diagram of the light emitting device illustrated inFIG. 1;

FIG. 5 is a plan view illustrating a light emitting device according toa second embodiment;

FIG. 6 is a sectional view taken along a direction of CC′ of the lightemitting device illustrated in FIG. 5;

FIG. 7 is a sectional view taken along a direction of DD′ of the lightemitting device illustrated in FIG. 5;

FIG. 8 is a circuit diagram of the light emitting device illustrated inFIG. 5;

FIG. 9 is a plan view illustrating a light emitting device according toa third embodiment;

FIG. 10 is a sectional view taken along a direction of EE′ of the lightemitting device illustrated in FIG. 9;

FIG. 11 is a sectional view illustrating a light emitting device packageincluding a light emitting device according to one embodiment;

FIG. 12 is an exploded perspective view of a lighting apparatusincluding the light emitting device package according to one embodiment;and

FIG. 13 is an exploded perspective view of a display apparatus includingthe light emitting device package according to one embodiment.

DESCRIPTION OF SPECIFIC EMBODIMENTS

Hereinafter, embodiments will be clearly understood from descriptionwith reference to the annexed drawings.

It will be understood that when an element is referred to as being “on”or “under” another element, it can be directly on/under the element, andone or more intervening elements may also be present. When an element isreferred to as being ‘on’ or ‘under’, ‘under the element’ as well as ‘onthe element’ can be included based on the element.

In the drawings, the thickness or size of each layer is exaggerated,omitted, or schematically illustrated for convenience of description andclarity. Also, the size or area of each constituent element does notentirely reflect the actual size thereof. Hereinafter, a light emittingdevice, a method for manufacturing the same and a light emitting packageincluding the light emitting device according to embodiments will bedescribed with reference to the annexed drawings.

FIG. 1 is a plan view illustrating a light emitting device 100 accordingto a first embodiment. FIG. 2 is a sectional view taken along adirection of AA′ of the light emitting device 100 illustrated in FIG. 1.FIG. 3 is a sectional view taken along a direction of BB′ of the lightemitting device 100 illustrated in FIG. 1.

Referring to FIGS. 1 to 3, the light emitting device 100 includes asubstrate 110, a buffer layer 115, a light emitting structure 120including a plurality of light emitting regions P1 to Pn (in which n isa natural number greater than 1), a conductive layer 130, an insulatinglayer 140, a first electrode unit 150, at least one connection electrode160-1 to 160-m (in which m is a natural number of 1 or more), at leastone intermediate pad 182, 184 and 186, and a second electrode unit 170.

The substrate 110 may be formed with a carrier wafer, a materialsuitable for growth of semiconductor materials. In addition, thesubstrate 110 may be formed with a highly thermo-conductive material andmay be a conductive substrate or an insulating substrate. For example,the substrate 110 may contain at least one of sapphire (Al₂O₃), GaN,SiC, ZnO, Si, GaP, InP, Ga₂O₃, and GaAs. A upper surface of thesubstrate 110 may be provided with a roughness pattern (not shown).

The buffer layer 115 is interposed between the substrate 110 and thelight emitting structure 120 and may be formed with a Group III-Vcompound semiconductor. The buffer layer 115 functions to reduce alattice constant between the substrate 110 and the light emittingstructure 120.

The light emitting structure 120 may be a semiconductor layer generatinglight and include a first conductive type semiconductor layer 122, anactive layer 124, and a second conductive type semiconductor layer 126.The light emitting structure 120 may have a structure including thefirst conductive type semiconductor layer 122, the active layer 124, andthe second conductive type semiconductor layer 126 sequentially stackedon the substrate 110.

The first conductive type semiconductor layer 122 may be formed with asemiconductor compound. The first conductive type semiconductor layer122 may be realized with a Group III-V or Group II-VI compoundsemiconductor or the like, and may be doped with a first conductivedopant.

For example, the first conductive type semiconductor layer 122 may be asemiconductor having a compositional formula of In_(x)Al_(y)Ga_(1-x-y)(0≦x≦1, 0≦y≦1, 0≦x+y≦1). For example, the first conductive typesemiconductor layer 122 may contain any one of InAlGaN, GaN, AlGaN,InGaN, AlN, and InN and may be doped with an n-type dopant (for example,Si, Ge, or Sn).

The active layer 124 is interposed between the first conductive typesemiconductor layer 122 and the second conductive type semiconductorlayer 126, and may generate light through energy generated duringrecombination of electrons and holes supplied from the first conductivetype semiconductor layer 122 and the second conductive typesemiconductor layer 126, respectively.

The active layer 124 may be formed with a semiconductor compound, forexample, a Group III-V or Group II-VI compound semiconductor, and mayhave a double-junction structure, a single well structure, a multiplewell structure, a quantum wire structure or a quantum dot structure.

When the active layer 124 is a single quantum well structure, it mayinclude a well layer having a compositional formula ofIn_(x)Al_(y)Ga_(1-x-y)N (0≦x≦1, 0≦y≦1, 0≦x+y≦1) and a barrier layerhaving a compositional formula of In_(a)Al_(b)Ga_(1-a-b)N (0≦a≦1, 0≦b≦1,0≦a+b≦1). The well layer may be made of a material having a lower bandgap than that of the barrier layer.

The second conductive type semiconductor layer 126 may be formed with asemiconductor compound. The second conductive type semiconductor layer126 may be realized with a Group III-V or Group II-VI compoundsemiconductor and be doped with a second conductive dopant.

For example, the second conductive type semiconductor layer 126 may be asemiconductor having a compositional formula of In_(x)Al_(y)Ga_(1-x-y)N(0≦x≦1, 0≦y≦1, 0≦x+y≦1). For example, the second conductive typesemiconductor layer 126 may contain any one of GaN, AlN, AlGaN, InGaN,InN, InAlGaN, AlInN, AlGaAs, GaP, GaAs, GaAsP, and AlGaInP and be dopedwith a p-type dopant (for example, Mg, Zn, Ca, Sr, or Ba).

The light emitting structure 120 may expose a part of the firstconductive type semiconductor layer 122. That is, the light emittingstructure 120 may expose the part of the first conductive typesemiconductor layer 122 by partially etching the second conductive typesemiconductor layer 126, the active layer 124 and the first conductivetype semiconductor layer 122. In this case, the surface of the firstconductive type semiconductor layer 122 exposed by mesa-etching may bepositioned to be lower than the lower surface of the active layer 124.

A conductive clad layer (not shown) may be interposed between the activelayer 124 and the first conductive type semiconductor layer 122, orbetween the active layer 124 and the second conductive typesemiconductor layer 126 and the conductive clad layer may be formed witha nitride semiconductor (for example, AlGaN).

The light emitting structure 120 may further include a third conductivesemiconductor layer (not shown) disposed under the second conductivetype semiconductor layer 126, and the third conductive semiconductorlayer may have an opposite polarity to the second conductive typesemiconductor layer 126. The first conductive type semiconductor layer122 may be realized with an n-type semiconductor layer and the secondconductive type semiconductor layer 126 may be realized with a p-typesemiconductor layer. Accordingly, the light emitting structure 120 mayinclude at least one of N-P, P-N, N-P-N and P-N-P junction structures.

The light emitting structure 120 may include a plurality of lightemitting regions spaced from one another P1 to Pn (in which n is anatural number greater than 1) and at least one boundary region S. Theboundary region S may be positioned between the light emitting regionsP1 to Pn (in which n is a natural number greater than 1). Alternatively,the boundary region S may be positioned on the circumferences of thelight emitting regions P1 to Pn (in which n is a natural number greaterthan 1). Each boundary region S may include a region where a part of thefirst conductive type semiconductor layer 122 is exposed, formed bymesa-etching the light emitting structure 120, in order to divide thelight emitting structure 120 into a plurality of light emitting regionsP1 to Pn (in which n is a natural number greater than 1).

The light emitting structure 120 of a single chip may be divided intothe light emitting regions P1 to Pn (in which n is a natural numbergreater than 1) through the at least one boundary region S.

The conductive layer 130 is disposed on the second conductive typesemiconductor layer 126. The conductive layer 130 reduces totalreflection and exhibits superior transmittance, thus increasing anextraction efficiency of light emitted from the active layer 124 to thesecond conductive type semiconductor layer 126. The conductive layer 130may be realized with a single or multiple layer structure using one ormore transparent oxide substances having high transmittance to lightemission wavelengths, such as indium tin oxide (ITO), tin oxide (TO),indium zinc oxide indium zinc tin oxide (IZTO), indium aluminum zincoxide (IAZO), indium gallium zinc oxide (IGZO), indium gallium tin oxide(IGTO), aluminum zinc oxide (AZO), aluminum tin oxide (ATO), galliumzinc oxide (GZO), IrOx, RuOx, RuOx/ITO, Ni, Ag, Ni/IrOx/Au orNi/IrOx/Au/ITO.

The insulating layer 140 is positioned on the light emitting regions P1to Pn (in which n is a natural number greater than 1) and the at leastone boundary region S. The insulating layer 140 may be formed of alight-transmissive insulating material, for example, SiO₂, SiO_(x),SiO_(x)N_(y), Si₃N₄, or Al₂O₃. For example, the insulating layer 140 maycover upper parts and sides of the light emitting regions P1 to Pn (inwhich n is a natural number greater than 1) and cover the at least oneboundary region S.

The first electrode unit 150 is disposed on the first conductive typesemiconductor layer 122 in one (for example, P1) of the light emittingregions P1 to Pn (for example, n=12) and may contact the firstconductive type semiconductor layer 122. The first electrode unit 150may include a first pad bonded to a wire (not shown) to supply a firstpower. In the embodiment of FIG. 1, the first electrode unit 150 mayserve as the first pad.

The second electrode unit 170 is disposed on the second conductive typesemiconductor layer 126 or conductive layer 130 in another (for example,P12) of the light emitting regions P1 to Pn (for example, n=12).

The second electrode unit 170 may contact the second conductive typesemiconductor layer 126 or the conductive layer 130. For example, thesecond electrode unit 170 may contact the conductive layer 130 of thefirst light emitting region (for example, P12) among the light emittingregions (for example, P1 to P12) connected in series.

The second electrode unit 170 may include a second pad bonded to a wire(not shown) to supply a second power. For example, the second electrodeunit 170 is disposed on the insulating layer 140 and may have a portionthat contacts the conductive layer 130 via the insulating layer 140.

The connection electrodes 160-1 to 160-m (in which m is a natural numberof 1 or more) are disposed on the insulating layer 140 and electricallyconnect a plurality of light emitting regions P1 to Pn (for example,n=12) in series. For example, the connection electrodes 160-1 to 160-m(for example, m=11) connect a plurality of light emitting regions (forexample, P1 to P12) in series, from a first light emitting region P1, inwhich the first electrode unit 150 is disposed, as a start point, to thetwelfth light emitting region P12 in which the second electrode unit 170is disposed, as an end point.

Each connection electrode (for example, 160-1) may electrically connectthe conductive layer 130 of one (for example, P1) of two adjacent lightemitting regions (for example, P1 and P2) to the first conductive typesemiconductor layer 122 of the other (for example, P2) thereof.

In another embodiment excluding the conductive layer 130, the connectionelectrode (for example, 160-1) may electrically connect the secondconductive type semiconductor layer 126 of one light emitting region(for example, P1) to the first conductive type semiconductor layer 122of the other light emitting region (for example, P2).

A plurality of light emitting regions P1 to Pn (in which n is a naturalnumber greater than 1) connected to one another in series included inthe light emitting device 100 are referred to as a 1^(st) light emittingregion to an n^(th) light emitting region in order. That is, the lightemitting region in which the first electrode unit 150 is disposed isreferred to as a 1^(st) light emitting region P1 and the light emittingregion in which the second electrode unit 170 is disposed is referred toas an n^(th) light emitting region Pn. Here, “adjacent light emittingregions” may be a k^(th) light emitting region and a K+1^(th) lightemitting region, the k^(th) connection electrode may electricallyconnect the k^(th) light emitting region to the K+1^(th) light emittingregion in series, where 1≦k≦(n−1).

That is, the k^(th) connection electrode may electrically connect thesecond conductive type semiconductor layer 126 or conductive layer 130of the k^(th) light emitting region to the first conductive typesemiconductor layer 122 of the k+1^(th) light emitting region.

For example, referring to FIG. 1, the k^(th) connection electrode 160-k(for example, k=2) may be positioned in the k^(th) light emitting regionPk (for example, P2), the k+1^(th) light emitting region Pk+1 (forexample, P3), and the boundary region S provided therebetween. Also, thek^(th) connection electrode 160-k (for example, k=2) may include atleast one first portion (for example, 101) that passes through theinsulating layer 140 and contacts the conductive layer 130 (or secondconductive type semiconductor layer 126) of the k^(th) light emittingregion Pk (for example, k=2). A full-lined circle illustrated in FIG. 1represents a first portion 101 of connection electrodes 160-1 to 160-m(for example, m=11). The insulating layer 140 may be disposed betweenthe light emitting structure 120 positioned on the boundary region S andthe connection electrodes 160-1 to 160-m (for example, m=11).

In addition, the k^(th) connection electrode 160-k (for example, k=2)may include at least one second portion (for example, 102) that passesthrough the insulating layer 140, the conductive layer 130, the secondconductive type semiconductor layer 126, and the active layer 124 of thek+1^(th) light emitting region Pk+1 (for example, P3) and contacts thefirst conductive type semiconductor layer 122. A dot-lined circleillustrated in FIG. 1 represents the second portion 102 of theconnection electrodes 160-1 to 160-m (for example, m=11).

The insulating layer 140 may be disposed between the connectionelectrode (for example, 160-2) and the conductive layer 130, between thesecond portion 102 of the connection electrode (for example, 160-2) andthe second conductive type semiconductor layer 126, and between thesecond portion 102 of the connection electrode (for example, 160-2) andthe active layer 124.

In general, in order to form an electrode connected to the firstconductive type semiconductor layer, mesa etching to expose the firstconductive type semiconductor layer by etching the light emittingstructure is performed. In general, the light emitting region of thelight emitting device is decreased in proportion to the mesh-etchedregion.

However, the second portion (for example, 102) of the k^(th) connectionelectrode 160-k (for example, k=2) may have a structure of a hole orgroove filled with an electrode material. For this reason, the lightemitting region lost by mesa etching is decreased and in thisembodiment, a light emitting area may be increased.

The insulating layer 140 functions to electrically insulate the k^(th)connection electrode 160-k (for example, k=2) from the conductive layer130, the second conductive type semiconductor layer 126 and the activelayer 124 of the k+1^(th) light emitting region Pk+1 (for example, P3).

A lower surface 103 of the second portion 102 of the k^(th) connectionelectrode 160-k (for example, k=2) may be disposed to be lower than alower surface of 104 of the active layer 124. The second portion 102 mayhave a structure of a hole or groove filled with an electrode material.

The intermediate pads 182, 184 and 186 are disposed on the insulatinglayer 140 in at least one of the light emitting regions P1 to Pn (inwhich n is a natural number greater than 1) and may be electricallyconnected to the second conductive type semiconductor layer 126 or theconductive layer 130. The intermediate pads 182, 184 and 186 may beregions bonded to wires (not shown) to supply a second power.

For example, the intermediate pads 182, 184 and 186 may be disposed onthe insulating layer 140 in at least one (for example, P3, P6, P9) ofthe light emitting regions (for example, P2 to P11), other than lightemitting regions (for example, P1 and P12) in which the first electrodeunit 150 and the second electrode portion 172 are positioned.

As shown in FIG. 3, the insulating layer 140 is interposed between theintermediate pad 182, 184 or 186, and the conductive layer 130, and theintermediate pad 182, 184 or 186 may be connected to any one of theconnection electrodes disposed in the same light emitting region (forexample, P3, P6, P9). For example, the first intermediate pad 182disposed on the insulating layer 140 in the third light emitting regionP3 may be connected to one terminal disposed in the third light emittingregion P3 of the third connection electrode 160-3.

However, in other embodiments, a part of the intermediate pad passesthrough the insulating layer and is directly connected to the conductivelayer. In this case, the intermediate pad and the connection electrodepositioned in the same light emitting region may be connected to eachother, or may be not connected.

FIG. 4 is a circuit diagram of the light emitting device 100 illustratedin FIG. 1. Referring to FIGS. 1 and 4, the light emitting device 100 hasa common single (−) terminal, for example, a first pad 150, and two ormore (+) terminals, for example, a second pad 170 and at least oneintermediate pad 182, 184 and 186.

Accordingly, in this embodiment, the light emitting device includes aplurality of (+) terminals, pads 170, 182, 184 and 186, thus enablinguse of various driving voltages and enabling control of emission oflight with various brightness levels.

This embodiment may be designed such that a part or entirety of lightemitting regions is driven by supplying a second power to any one of theintermediate pads 182, 184 and 186, and the second pad 170 according toapplied driving voltage.

In addition, in this embodiment, the light emitting area can beincreased, current is dispersed and light-emission efficiency can thusbe improved, because the connection electrodes 160-1 to 160-m (in whichm is a natural number of or more) point-contact the conductive layer 130or the first conductive type semiconductor layer 122.

The 1^(st) to n^(th) light emitting regions P1 to Pn (in which n is anatural number greater than 1) are sequentially connected in seriesthrough the connection electrodes 160-1 to 160-m (in which m is anatural number of 1 or more). That is, the light emitting regions P1 toPn (in which n is a natural number greater than 1) are sequentiallyconnected in series from the first light emitting region P1, where thefirst electrode unit 150 is disposed, to the n light emitting region Pn,where the second electrode unit 170 is disposed.

The light emitting regions P1 to Pn (in which n is a natural numbergreater than 1) sequentially connected in series are divided into 1^(st)to i^(th) (in which i is a natural number satisfying 1<i≦j<n) lightemitting region groups. Respective light emitting regions P1 to Pn (inwhich n is a natural number greater than 1) may be included in differentgroups.

The light emitting regions that belong to the respective groups may beconnected to each other in series through the connection electrodes160-1 to 160-m (in which m is a natural number of 1 or more) or theintermediate pads 182, 184 and 186.

In this embodiment, an area of the light emitting regions that belong tothe same group may be identical, so that, in a case in which one groupis driven, a current is uniformly distributed in the light emittingregions that belong to the group and light emission efficiency is thusimproved, because the light emitting regions that at least belong to thesame group are simultaneously driven or are not driven.

Areas of light emitting regions that belong to different groups may bedifferent. For example, at least one of a transverse length and alongitudinal length of the light emitting regions that belong todifferent groups may be different. Referring to FIG. 1, transverselengths of the light emitting regions that belong to different groupsmay be identical, but the longitudinal lengths thereof may be different.

An area of the light emitting region that belongs to one of adjacentgroups connected to one another in series may be different from an areaof the light emitting region that belongs to the other thereof. Forexample, the area of the light emitting region included in an i−^(th)group is greater than an area of light emitting region that belongs toan i^(th) group.

In addition, the area of the light emitting region that belongs to eachgroup may decrease from the first group to the last group (i=j) inorder. For example, transverse lengths of light emitting regions thatbelong to respective groups are identical (X1=X2=X3), but longitudinallengths thereof may decrease (Y1>Y2>Y3>Y4). For example, equations ofX1=X2=X3 and Y1:Y2:Y3:Y4=1:0.9˜0.7:0.60˜0.5:0.4˜0.1 may be satisfied.

The first group may include a light emitting region where the firstelectrode unit 150 is disposed. For example, the first electrode unit150 may be disposed on the first conductive type semiconductor layer 122in the first light emitting region among the light emitting regions thatbelong to the first group. The first light emitting region may be alight emitting region that is first connected in series, among the lightemitting regions connected in series that belong to the first group.Referring to FIG. 1, for example, the first group may include a firstlight emitting region P1, a second light emitting region P2, and a thirdlight emitting region P3.

The last group (i=j) may include a light emitting region where thesecond electrode unit 170 is positioned. For example, the secondelectrode unit 170 may be disposed on the second conductive typesemiconductor layer 126 or the conductive layer 130 in the last lightemitting region among light emitting regions of the last group (i=j).The last light emitting region may be a light emitting region that islast connected in series, among the light emitting regions connected inseries that belong to the j^(th) group.

Each group other than the last group (i=j) may include a light emittingregion where the intermediate pad is disposed. For example, intermediatepads (for example, 182, 184 and 186) may be disposed on the secondconductive type semiconductor layer 126 or the conductive layer 130 inthe last light emitting region among the light emitting regions thatbelong to the 1^(st) group to the j−1^(th) group.

In this embodiment, the first electrode unit 150 is a common electrodeto supply a first power to the light emitting regions P1 to Pn (in whichn is a natural number greater than 1), and a second power is supplied toany one of the intermediate pads 182, 184, and 186 and the secondelectrode unit 170. Accordingly, the group emitting light may bedetermined depending on an element, i.e., the intermediate pad 182, 184or 186, or the second electrode unit 170, to which the second power issupplied.

For example, when the second power is supplied to the first intermediatepad 182, light emitting regions (for example, P1 to P3) that belong tothe first group may emit light. Alternatively, when the second power issupplied to the second intermediate pad 184, light emitting regions (forexample, P1 to P6) that belong to the first and second groups may emitlight.

Alternatively, when the second power is supplied to the thirdintermediate pad 186, light emitting regions (for example, P1 to P9)that belong to the first, second and third groups may emit light.

Alternatively, when the second power is supplied to the second electrodeunit 170, light emitting regions (for example, P1 to P12) that belong tothe first, second, third and fourth groups may emit light.

As such, in this embodiment, because the group closer to the commonelectrode, i.e., the first electrode unit 150, is probabilistically morefrequently used, reliability and efficiency of the light emitting devicecan be improved through increase in area of probabilistically morefrequently used light emitting region. In addition, in this embodiment,an area of the light emitting region may be controlled according to theintended purpose.

FIG. 5 is a plan view illustrating a light emitting device 200 accordingto a second embodiment. FIG. 6 is a sectional view taken along adirection of CC′ of the light emitting device 200 illustrated in FIG. 5.FIG. 7 is a sectional view taken along a direction of DD′ of the lightemitting device 200 illustrated in FIG. 5. The same drawing referencenumerals as in FIGS. 1 to 3 represent the same configuration andcontents described above are omitted or summarized.

Referring to FIGS. 5 to 7, the light emitting device 200 includes asubstrate 110, a buffer layer 115, a light emitting structure 120divided into a plurality of light emitting regions P1 to Pn (in which nis a natural number greater than 1), a conductive layer 130, aninsulating layer 140, a first electrode unit 250, at least oneconnection electrode 260-1 to 260-m (in which m is a natural number of 1or more), at least one intermediate pad 252, 254 and 256, and a secondelectrode unit 270.

The first electrode unit 250 is disposed on the first conductive typesemiconductor layer 122 in one light emitting region (for example, P12)among the light emitting regions P1 to Pn (for example, n=12) and maycontact the first conductive type semiconductor layer 122. The firstelectrode unit 250 may include a first pad bonded to a wire (not shown)to supply a first power. In the embodiment of FIG. 5, the firstelectrode unit 250 may serve as the first pad.

The second electrode unit 270 is disposed on the second conductive typesemiconductor layer 126 or the conductive layer 130 in another lightemitting region (for example, P1) of the light emitting regions P1 to Pn(for example, n=12). Also, the second electrode unit 270 may contact thesecond conductive type semiconductor layer 126 or the conductive layer130.

The second electrode unit 270 may include a second pad bonded to a wire(not shown) to supply a second power. In another embodiment, the secondelectrode unit 270 may further include a branch electrode (not shown)that extends from the second pad.

For example, the second electrode unit 270 is disposed on the conductivelayer 130 in the first light emitting region P1 among the light emittingregions connected in series, and the first electrode unit 250 may bedisposed on the first conductive type semiconductor layer 122 in thelast light emitting region P12.

The insulating layer 140 may be disposed in a plurality of lightemitting regions P1 to Pn (in which n is a natural number greaterthan 1) and on the boundary region S. The connection electrodes 260-1 to260-m (for example, m=11) are disposed on the insulating layer 140 andelectrically connect a plurality of light emitting regions P1 to Pn (forexample, n=12) in series.

Each connection electrode (for example, 260-2) may electrically connectthe first conductive type semiconductor layer 122 of one (for example,P2) of the adjacent light emitting regions (for example, P2 and P3) tothe second conductive type semiconductor layer 126 or the conductivelayer 130 in the other (for example, P3) thereof.

That is, the k^(th) connection electrode may electrically connect thefirst conductive type semiconductor layer 122 of the k^(th) lightemitting region to the second conductive type semiconductor layer 126 orthe conductive layer 130 of the k+1^(th) light emitting region.

For example, referring to FIG. 6, the k^(th) connection electrode 260-K(for example, k=2) may be disposed in the k^(th) light emitting regionPk (for example, k=2), the k+1^(th) light emitting region Pk+1 (forexample, P3), and the boundary region S provided therebetween. Also, thek^(th) connection electrode (for example, 260-k, k=2) may have at leastone first portion (for example, 201) that passes through the insulatinglayer 140 and contacts the conductive layer 130 (or second conductivetype semiconductor layer 126) of the k+1^(th) light emitting region Pk+1(for example, P3). The insulating layer 140 may be interposed betweenthe light emitting structure 120 disposed in the boundary region S andthe connection electrode 260-1 to 260-m (in which m is a natural numberof 1 or more).

In addition, the k^(th) connection electrode 260-k (for example, k=2)may include at least one second portion (for example, 202) that passesthrough the insulating layer 140, the conductive layer 130, the secondconductive type semiconductor layer 126 and the active layer 124 of thek^(th) light emitting region Pk (for example, k=2) and contacts thefirst conductive type semiconductor layer 122. The insulating layer 140may be disposed between the k^(th) connection electrode 260-k (forexample, k=2) and the conductive layer 130, between the second portion202 of the k^(th) connection electrode 260-k (for example, k=2) and thesecond conductive type semiconductor layer 126, and between the secondportion 202 of the k^(th) connection electrode 260-k (for example, k=2)and the active layer 124.

The intermediate pads 252, 254 and 256 are disposed on the firstconductive type semiconductor layer 122 in at least one of the lightemitting regions P1 to Pn (in which n is a natural number greater than1). The intermediate pads 252, 254 and 256 may be bonded to wires (notshown) to supply a first power.

A part of the first conductive type semiconductor layer 122 is exposedby mesa-etching at least one (for example, P3, P6, and P9) of the lightemitting regions (for example, P1 to P12) and the intermediate pads 252,254 and 256 may be disposed in a part of the exposed first conductivetype semiconductor layer 122.

For example, the intermediate pads 252, 254 and 256 may be disposed onthe first conductive type semiconductor layer 122 in at least one lightemitting region (for example, P3, P6, P9) among the light emittingregions (for example, P2 to P11) other than light emitting regions (forexample, P1 and P12) where the first electrode unit 250 and the secondelectrode unit 270 are positioned.

FIG. 8 is a circuit diagram of the light emitting device 200 illustratedin FIG. 5. Referring to FIGS. 5 and 8, the light emitting device 200 hasa common single (+) terminal, for example, a second pad 270, and two ormore (−) terminals, for example, a first pad 250 and at least oneintermediate pad 252, 254 and 256.

Accordingly, in this embodiment, the light emitting device includes twoor more (−) terminals, pads 250, 252, 254 and 256, thus enabling use ofvarious driving voltages and enabling control of emission of light withvarious brightness levels.

The 1^(st) to n^(th) light emitting regions P1 to Pn (in which n is anatural number greater than 1) are sequentially connected in seriesthrough the connection electrode 260-1 to 260-m (in which m is a naturalnumber of 1 or more). That is, the light emitting regions P1 to Pn (inwhich n is a natural number greater than 1) are sequentially connectedin series from the first light emitting region P1, where the secondelectrode unit 270 is disposed, to the n light emitting region Pn (forexample n=12), where the first electrode unit 250 is disposed.

The light emitting regions P1 to Pn (in which n is a natural numbergreater than 1) sequentially connected in series are divided into 1^(st)to i^(th) (in which i is a natural number satisfying 1<i≦j<n) lightemitting region groups. Respective light emitting regions P1 to Pn (inwhich n is a natural number greater than 1) may be included in differentgroups.

The light emitting regions that belong to the respective groups may beconnected to each other in series through the connection electrode 260-1to 260-m (in which m is a natural number of 1 or more) or intermediatepads 252, 254 and 256.

In order to improve light emission efficiency, areas of light emittingregions that belong to the same group may be identical. However, areasof the light emitting regions that belong to different groups may bedifferent. For example, at least one of a transverse length and alongitudinal length of the light emitting regions that belong todifferent groups may be different. Referring to FIG. 5, transverselengths of the light emitting regions that belong to different groupsmay be identical (X1=X2=X3), but the longitudinal lengths thereof may bedifferent (Y1≠Y2≠Y3≠Y4).

An area of the light emitting region that belongs to one of adjacentgroups connected to one another in series may be different from an areaof the light emitting region that belongs to the other thereof. Forexample, the area of the light emitting region included in an i−1^(th)group is greater than an area of light emitting region that belongs toan i^(th) group.

In addition, the area of the light emitting region that belongs to eachgroup may decrease from the first group to the last group (i=j) in thisorder. For example, transverse lengths of light emitting regions thatbelong to respective groups are identical (X1=X2=X3), but longitudinallengths thereof may decrease (Y1>Y2>Y3>Y4). For example, equations ofX1=X2=X3 and Y1:Y2:Y3:Y4=1:0.9˜0.7:0.6˜0.5:0.4˜0.1 may be satisfied.

The first group may include a light emitting region (for example, P1)where the second electrode unit 270 is disposed. For example, the secondelectrode unit 270 may be disposed on the second conductive typesemiconductor layer 126 or the conductive layer 130 of the first lightemitting region (for example, P1) among light emitting regions (forexample, P1 to P3) included in the first group.

The last group (i=j) may include a light emitting region where the firstelectrode unit 250 is disposed. For example, the first electrode unit250 may be disposed on the first conductive type semiconductor layer 122in the last light emitting region (for example, P12) among the lightemitting regions (for example, P10, P11, and P12) that belong to thelast group (j^(th) group).

The respective groups (for example, i=2 to i=j) other than the firstgroup (for example, i=1) may include a light emitting region in whichthe intermediate pad is disposed. For example, intermediate pads (forexample, 252, 254, and 256) may be disposed on the first conductive typesemiconductor layer 122 in the last light emitting region among thelight emitting regions that belong to the second group to the j^(th)group.

In this embodiment, the second electrode unit 270 is a common electrodeto supply a second power to the light emitting regions, and a firstpower is supplied to any one of the intermediate pads 252, 254, and 256and the first electrode unit 250. Accordingly, the group emitting lightmay be determined depending on an element, i.e., the intermediate pad252, 254 or 256, or the first electrode unit 250, to which the firstpower is supplied.

As such, in this embodiment, because the group closer to the commonelectrode, i.e., the second electrode unit 270, is probabilisticallymore frequently used, reliability and efficiency of the light emittingdevice can be improved through increase in an area of probabilisticallymore frequently used light emitting region. In addition, in thisembodiment, an area of the light emitting region may be controlledaccording to the intended purpose.

FIG. 9 is a plan view illustrating a light emitting device 300 accordingto a third embodiment. FIG. 10 is a sectional view taken along adirection of EE′ of the light emitting device 300 illustrated in FIG. 9.

Referring to FIGS. 9 and 10, the light emitting device 300 includes alight emitting structure 10 divided into a plurality of light emittingregions P1 to Pn (in which n is a natural number greater than 1), aprotective layer 20, a current blocking layer 30, a plurality of metallayers 40-1 to 40-n (in which n is a natural number greater than 1), aninsulating layer 50, a second electrode unit 60, a passivation layer 25,a first electrode unit 92, at least one connection electrode 360-1 to360-m (in which m is a natural number of 1 or more), and at least oneintermediate pad 94, 96 and 98.

The light emitting structure 10 may generate light and include acompound semiconductor layer containing a plurality of Group III-Velements. As shown in FIG. 10, the light emitting structure 10 mayinclude a first conductive type semiconductor layer 16, an active layer14 and a second conductive type semiconductor layer 12.

The second conductive type semiconductor layer 12 may be positionedunder the first conductive type semiconductor layer 16 and the activelayer 14 may be positioned between the first conductive typesemiconductor layer 16 and the second conductive type semiconductorlayer 12. The light emitting structure 10 may include a plurality oflight emitting regions P1 to Pn (in which n is a natural number greaterthan 1) spaced from one another and at least one boundary region S. Thefirst conductive type semiconductor layer 16, the active layer 14 andthe second conductive type semiconductor layer 12 may be the same, asdescribed in FIGS. 1 and 2.

The protective layer 20 may be disposed under the boundary region S. Theboundary region S or protective layer 20 may define light emittingregions P1 to Pn (in which n is a natural number greater than 1). Theprotective layer 20 protects light emitting regions P1 to Pn (in which nis a natural number greater than 1) and thereby prevents deteriorationin reliability of the light emitting device 300 during isolation etchingto divide the light emitting structure 20 into a plurality of lightemitting regions P1 to Pn (in which n is a natural number greater than1).

The light emitting regions P1 to Pn (for example, n=12) may have astructure in which the second conductive type semiconductor layer 12,the active layer 14 and the first conductive type semiconductor layer 16are stacked in a vertical direction. Here, the vertical direction may bea direction from the second conductive type semiconductor layer 12 tothe first conductive type semiconductor layer 16, or a directionvertical to the support layer 66.

The metal layers 40-1 to 40-n (in which n is a natural number greaterthan 1) may be disposed under the light emitting structure 10. The metallayers 40-1 to 40-n (in which n is a natural number greater than 1) maybe spaced from one another under the second conductive typesemiconductor layer 12 in the corresponding one of the light emittingregions P1 to Pn (in which n is a natural number greater than 1).

FIG. 10 illustrates only metal layers 40-1, 40-6, 40-7, and 40-12corresponding to the light emitting regions (for example, P1, P6, P7,P12), respectively, and does not illustrate metal layers 40-2 to 40-5,and 40-8 to 40-11 corresponding to other light emitting regions P2 toP5, and P8 to P11. Each metal layer 40-1 to 40-n (for example, n=12) mayinclude at least one of an ohmic layer 42 and a reflective layer 44.

The ohmic layer 42 is disposed under the light emitting regions P1 to Pn(for example, n=12) and may ohmic-contact the second conductive typesemiconductor layer 12. For example, the ohmic layer 42 may contain atleast one of In, Zn, Ag, Sn, Ni, and Pt.

The reflective layer 44 may be disposed under the ohmic layer 42 in thelight emitting regions P1 to Pn (for example, n=12) and reflects lightemitted from the light emitting structure 10 to improve light extractionefficiency of the light emitting device 300. The reflective layer 44 maycontact the outermost side of the ohmic layer 42 and surround the ohmiclayer 42.

The reflective layer 44 may contain at least one of a reflective metalor an alloy thereof, for example, at least one of Ag, Ni, Al, Rh, Pd,Ir, Ru, Mg, Zn, Pt, Au, and Hf. In addition, the reflective layer 44 mayhave a single or multiple layer structure using a light-transmissiveconductive oxide, for example, indium zinc oxide (IZO), indium zinc tinoxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zincoxide (IGZO), indium gallium tin oxide (IGTO), aluminum zinc oxide(AZO), antimony tin oxide (ATO) or the like. In addition, the reflectivelayer 44 may have a multilayer structure containing a composite of metaland conductive oxide, such as IZO/Ni, AZO/Ag, IZO/Ag/Ni, or AZO/Ag/Ni.

In another embodiment, without separately forming the ohmic layer 42, itmay be designed that the reflective layer ohmic-contacts the secondconductive type semiconductor layer 12 by using a material for thereflective layer 44 as a material that ohmic-contacts the secondconductive type semiconductor layer 12.

The current blocking layer 30 may be disposed under the secondconductive type semiconductor layer 12 in the light emitting structure10. For example, the current blocking layer 30 may be disposed betweenthe second conductive type semiconductor layer 12 and the metal layer40-1 to 40-n (in which n is a natural number greater than 1) in thelight emitting regions P1 to Pn (for example, n=12). The currentblocking layer 30 reduces concentration of current in a certain regionof the light emitting regions P1 to Pn (for example, n=12) and therebyimproves light emission efficiency of the light emitting device 300.

The current blocking layer 30 may be disposed to correspond to theconnection electrodes 360-1 to 360-m (in which m is a natural number of1 or more), or the first electrode unit 92, or intermediate pads 94, 96and 98, and at least partially overlaps the connection electrodes 360-1to 360-m, the first electrode unit 92 or intermediate pads 94, and 98 ina vertical direction. The current blocking layer 30 may have a patterncorresponding to a pattern of the connection electrode 360-1 to 360-m(in which m is a natural number of 1 or more). Here, the verticaldirection may be a direction from the second conductive typesemiconductor layer 12 to the first conductive type semiconductor layer16.

The current blocking layer 30 may be formed with a material having alower electrical conductivity than metal layers 40-1 to 40-n (in which nis a natural number greater than 1), a material that Schottky-contactsthe second conductive type semiconductor layer 12, or an electricalinsulating material. For example, the current blocking layer 30 maycontain at least one of ZnO, SiO₂, SiON, Si₃N₄, Al₂O₃, TiO₂, Ti, Al, andCr.

The second electrode unit 60 is positioned under the insulating layer 50and may be electrically connected to the metal layer (for example, 40-1)that contacts the second conductive type semiconductor layer 12 in one(for example, P1) of the light emitting regions P1 to Pn (for example,n=12). The second electrode unit 60 may supply a second power to the onelight emitting region (for example, P1).

The second electrode unit 60 may include a barrier layer 62, a bondinglayer 64 and a support layer 66.

The barrier layer 62 is disposed under the reflective layer 44 in thelight emitting regions P1 to Pn (for example, n=12), and prevents metalions of the support layer 66 from passing through the reflective layer44 and the ohmic layer and then being transferred or diffused to thelight emitting structure. The barrier layer 62 contains a barrier metalmaterial, for example at least one of Pt, Ti, W, V, Fe, and Mo, and mayhave a single or multilayer structure.

The barrier layer 62 is positioned under the insulating layer 50 and maybe electrically connected to the metal layer (for example, 40-1) thatcontacts the second conductive type semiconductor layer 12 in one (forexample, P1) of the light emitting regions P1 to Pn (for example, n=12).

Since the second conductive type semiconductor layer 12 in the firstlight emitting region (for example, P1) among the light emitting regionsP1 to Pn (for example, n=12) is electrically connected to the barrierlayer 62, the second power may be supplied through the barrier layer 62to the first light emitting region (for example, P1). The reason forthis is that the barrier layer 62 is electrically connected to thesupport layer 66 described below and the second power may be suppliedthrough the support layer 66.

The insulating layer 50 surrounds the metal layers 40-1 to 40-n (forexample, n=12). The insulating layer 50 is disposed between the metallayers 40-1 to 40-n (for example, n=12), and between the metal layer40-2 to 40-n (for example, n=12), other than the metal layer (forexample, 40-1) connected to the second electrode unit 60, and the secondelectrode unit 60.

For example, the insulating layer 50 electrically insulates the metallayers 40-1 to 40-n (for example, n=9) and electrically insulates themetal layer 40-2 to 40-n (for example, n=9), other than the first metallayer (for example, 40-1), and the second electrode unit 60.

The insulating layer 50 may be formed with an insulating material, forexample, at least one of Al₂O₃, SiO₂, Si₃N₄, TiO₂, and AlN, and may havea single or multiple layer structure.

The support layer 66 is disposed under the barrier layer 62, supportsthe light emitting structure 10, and supplies power to the lightemitting structure 10, together with the first electrode unit 92. Thesupport layer 66 is a conductive material and is a semiconductormaterial containing a metal material such as copper (Cu), gold (Au),nickel (Ni), molybdenum (Mo), or copper-tungsten (Cu—W), or at least oneof Si, Ge, GaAs, ZnO, SiC, and SiGe.

The bonding layer 64 is disposed between the barrier layer 62 and thesupport layer 66. The bonding layer 64 is interposed between the barrierlayer 62 and the support layer 66 to bond the two layers. The bondinglayer 64 is formed to bond the support layer 66 in a bonding manner. Forthis reason, when the support layer 66 is formed using a method such asplating or deposition, or the support layer 66 is a semiconductor layer,the bonding layer 64 may be omitted. The bonding layer 64 contains abonding metal material, for example, at least one of Au, Sn, Ni, Nb, In,Cu, Ag and Pd.

The first electrode unit 92 is disposed on the first conductive typesemiconductor layer 16 in one (for example, P12) among the lightemitting regions P1 to Pn (for example, n=12). The first electrode unit92 may include a first pad bonded to a wire to supply a first power. Inthe embodiment of FIG. 9, the first electrode unit 92 may serve as thefirst pad. The upper surface of the first conductive type semiconductorlayer 16 may be provided with a roughness 16-1 in order to improve lightextraction efficiency.

The passivation layer 25 may be disposed on the light emitting regionsP1 to Pn (in which n is a natural number greater than 1) and the atleast one boundary region S. The passivation layer 25 may be disposed onsides and upper surfaces of light emitting regions P1 to Pn (forexample, n=12) and on the at least one boundary region S.

For example, the passivation layer 25 may be disposed on the side of thefirst conductive type semiconductor layer 16, the side of the activelayer 14 and the side of the second conductive type semiconductor layer12 included in the each light emitting region P1 to Pn (for example,n=12), and the passivation layer 25 may be disposed on the upper surfaceof the first conductive type semiconductor layer 16 in each lightemitting region P1 to Pn (for example, n=12). In addition, thepassivation layer 25 may be disposed on the protective layer 20 of theboundary region S. The first electrode unit 92 may be exposed from thepassivation layer 25.

The connection electrodes 360-1 to 360-m (in which m is a natural numberof 1 or more) may be disposed on the passivation layer 25 positioned inadjacent light emitting regions and boundary regions providedtherebetween.

Each connection electrode 360-1 to 360-m (in which m is a natural numberof 1 or more) electrically connects the first conductive typesemiconductor layer 16 in one of adjacent light emitting regions to thesecond conductive type semiconductor layer 12 in the other lightemitting region thereof. The k^(th) connection electrode 360-k (forexample, k=6) may electrically connect the first conductive typesemiconductor layer 16 of the k^(th) light emitting region Pk (forexample, k=6) to the second conductive type semiconductor layer 12 ofthe K+1^(th) light emitting region Pk+1 (for example, P7).

The connection electrode 360-1 to 360-m (in which m is a natural numberof 1 or more) may include at least one first portion 301 that passesthrough the passivation layer 25, the first conductive typesemiconductor layer 16 and the active layer 14, and contacts the secondconductive type semiconductor layer 12 in one of adjacent light emittingregions.

In addition, the connection electrode 360-1 to 360-m (in which m is anatural number of 1 or more) may include at least one second portion 302that passes through the passivation layer 25 and contacts the firstconductive type semiconductor layer 16 in the other of the adjacentlight emitting regions.

The k^(th) light emitting region may be positioned in the k^(th) lightemitting region, the k+1^(th) light emitting region, and the boundaryregion S provided therebetween.

For example, the k^(th) connection electrode 360-k may include at leastone first portion (for example, 301) that passes through the passivationlayer 25, the first conductive type semiconductor layer 16 and theactive layer 14, and contacts the second conductive type semiconductorlayer 12 of the K+1^(th) light emitting region (for example, Pk+1). Thedot-lined circle shown in FIG. 9 represents the first portion 301 of theconnection electrodes 360-1 to 360-m (for example, m=11).

The passivation layer 25 may be positioned between the first portion 301of the k^(th) connection electrode (for example, 360-k) and the firstconductive type semiconductor layer 16, and between the first portion301 of the k^(th) connection electrode (for example, 360-k) and theactive layer 14. That is, the passivation layer 25 functions toelectrically insulate the first portion 301 of the k^(th) connectionelectrode (for example, 360-k) from the first conductive typesemiconductor layer 16 and the active layer 14 of the K+1^(th) lightemitting region (for example, Pk+1).

In addition, the k^(th) connection electrode 360-k may include at leastone second portion (for example, 302) that passes through thepassivation layer 25 of the k^(th) light emitting region (for example,Pk) and contacts the first conductive type semiconductor layer 16. Afull-lined circle illustrated in FIG. 9 represents the second portion302 of the connection electrodes 360-1 to 360-m (for example, m=11).

A lower surface of the first portion 301 of the k^(th) connectionelectrode (for example, 360-k) may be disposed to be lower than a lowersurface of the active layer 124. The first portion 301 may have astructure of a hole or groove filled with an electrode material.

The intermediate pads 94, 96 and 98 are disposed on the first conductivetype semiconductor layer 16 in at least one of the light emittingregions P1 to Pn (in which n is a natural number greater than 1) and maybe electrically connected to the first conductive type semiconductorlayer 16. The intermediate pads 94, 96 and 98 may be bonded to wires(not shown) to supply a first power.

The intermediate pads 94, 96 and 98 may be disposed on the firstconductive type semiconductor layer 16 in at least one, for example, P3,P6, P9 among light emitting regions (for example, P2 to P11) other thanthe light emitting region (for example, P12) in which the firstelectrode unit 92 is disposed and the light emitting region (forexample, P1) to which the second electrode unit 60 is electricallyconnected.

As shown in FIG. 9, the intermediate pad (for example, 94) may beelectrically connected to one terminal of the connection electrode (forexample, 360-3) disposed in the same light emitting region (for example,P3). However, in other embodiments, the intermediate pad (for example,94) may be electrically connected to or separated from the connectionelectrode (for example, 360-3) disposed in the same light emittingregion (for example, P3).

This embodiment may be designed such that a part or entirety of lightemitting regions P1 to Pn (in which n is a natural number of 1 orhigher) is driven by supplying a first power to any one of the firstelectrode unit 92 and the intermediate pads 94, 96 and 98 according toapplied driving voltage.

The 1^(st) to n^(th) light emitting regions P1 to Pn (in which n is anatural number greater than 1) may be sequentially connected in seriesthrough the connection electrodes 360-1 to 360-m (in which m is anatural number of 1 or more). That is, the light emitting regions P1 toPn (in which n is a natural number greater than 1) may be sequentiallyconnected in series from the 1^(st) light emitting region P1electrically connected to the second electrode unit 60 to the n^(th)light emitting region Pn (for example, n=12), where the first electrodeunit 92 is disposed.

The light emitting regions P1 to Pn (in which n is a natural numbergreater than 1) sequentially connected in series are divided into 1^(st)to i^(th) (in which i is a natural number satisfying 1<i≦j<n) lightemitting region groups. Respective light emitting regions P1 to Pn (inwhich n is a natural number greater than 1) may be included in differentgroups.

The light emitting regions that belong to the respective groups may beconnected in series to each other through the connection electrodes360-1 to 360-m (in which m is a natural number of 1 or more) or theintermediate pads 94, 96, and 98. Areas of the light emitting regionsthat belong to the same group may be designed to be identical in orderto uniformly distribute current and thereby improve light emissionefficiency.

The areas of light emitting regions that belong to different groups maybe different. For example, at least one of a transverse length and alongitudinal length of the light emitting regions that belong todifferent groups may be different. Referring to FIG. 9, transverselengths of the light emitting regions that belong to different groupsmay be identical, but the longitudinal lengths thereof may be different.

An area of the light emitting region that belongs to one of adjacentgroups connected to one another in series may be different from an areaof the light emitting region that belongs to the other thereof. Forexample, the area of the light emitting region included in an i−1^(th)group is greater than an area of a light emitting region that belongs toan i^(th) group.

In addition, the area of the light emitting region that belongs to eachgroup may decrease from the first group to the last group (i=j) in thisorder. For example, transverse lengths of light emitting regions thatbelong to respective groups are identical (X1=X2=X3), but longitudinallengths thereof may decrease (Y1>Y2>Y3>Y4). For example, equations ofX1=X2=X3 and Y1:Y2:Y3:Y4=1:0.9˜0.7:0.6˜0.5:0.4˜0.1 may be satisfied.

The first group may include a light emitting region electricallyconnected to the second electrode unit 60. For example, the secondelectrode unit 60 may be connected to the metal layer (for example,40-1) in the first light emitting region (for example, P1) among thelight emitting regions (for example, P1, P2, and P3) that belongs to thefirst group.

The last group (i=j) may include a light emitting region where the firstelectrode unit 92 is disposed. For example, the first electrode unit 92may be disposed on the first conductive type semiconductor layer 16 inthe last light emitting region (for example, P12) among the lightemitting regions (for example, P10, P11 and P12) of the last group(i=j).

Respective groups (i^(th) to j−1^(th) groups) other than the last group(i=j) may include a light emitting region where the intermediate pad isdisposed. For example, intermediate pads (for example, 94, 96 and 98)may be disposed on the first conductive type semiconductor layer 16 inthe last light emitting region among the light emitting regions thatbelong to the 1^(st) group to the j−1^(th) group.

In this embodiment, the second electrode unit 60 is a common electrodeto supply a second power to the light emitting regions P1 to Pn (inwhich n is a natural number greater than 1), and a first power issupplied to any one of the intermediate pads 94, 96 and 98 and thesecond electrode unit 92. Accordingly, the group emitting light may bedetermined depending on an element, i.e., the intermediate pad 94, 96and 98, or the second electrode unit 92, to which the first power issupplied.

As such, in this embodiment, because the group closer to the commonelectrode, i.e., the second electrode unit 60, is probabilistically morefrequently used, reliability and efficiency of the light emitting devicecan be improved through increase in area of probabilistically morefrequently used light emitting region. In addition, in this embodiment,an area of the light emitting region may be controlled according tointended purpose.

FIG. 11 is a sectional view illustrating a light emitting device packageincluding a light emitting device in accordance with one embodiment.

With reference to FIG. 11, the light emitting device package includes apackage body 510, a first lead frame 512, a second lead frame 514, alight emitting device 520, a reflective plate 525, wires 522 and 524,and a resin layer 540.

The package body 510 has a structure with a cavity at one side regionthereof. Here, the side wall of the cavity may be inclined. The packagebody 510 may be formed of a substrate having excellent insulation andthermal conductivity, such as a silicon-based wafer level package, asilicon substrate, silicon carbide (SiC), aluminum nitride (AlN), or thelike, and may have a structure in which plural substrates are stacked.This embodiment is not limited to the above-described material,structure and shape of the package body 510.

The first lead frame 512 and the second lead frame 514 are disposed onthe surface of the package body 510 so as to be electrically separatedfrom each other in consideration of heat dissipation or mounting of thelight emitting device 520. The light emitting device 520 is electricallyconnected to the first lead frame 512 and the second lead frame 514through the first wire 522 and the second wire 524. Here, the lightemitting device 520 may be one of the light emitting devices 100, 200and 300 according to the afore-mentioned embodiments.

For example, in the light emitting device 100 illustrated in FIG. 1, thefirst electrode unit 150 is electrically connected to the second leadframe 514 through the second wire 524. Also, one of the second electrodeunit 170 and the intermediate pads 182, 184 and 186 may be electricallyconnected to the first lead frame 512 through the first wire 522.

For example, in the light emitting device 200 illustrated in FIG. 5, thesecond electrode unit 270 is electrically connected to the first leadframe 512 through the first wire 522. Also, one of the first electrodeunit 250 and intermediate pads 252, 254 and 256 may be electricallyconnected to the second lead frame 514 through the second wire 524.

For example, in the light emitting device 300 illustrated in FIG. 9, thesupport layer 66 is bonded to the first lead frame 512. Also, one of thefirst electrode unit 92 and intermediate pads 94, 96 and 98 may beelectrically connected to the second lead frame 514 through the secondwire 524.

The reflective plate 525 may be formed on the side wall of the cavity ofthe package body 510 to guide light emitted from the light emittingdevice 520 in a designated direction. The reflective plate 525 may beformed of a light reflective material, for example, metal coating ormetal flakes.

The resin layer 540 surrounds the light emitting device 520 locatedwithin the cavity of the package body 510, and protects the lightemitting device 520 from external environments. The resin layer 540 maybe formed of a colorless transparent polymer resin material, such asepoxy or silicon. The resin layer 540 may include phosphors to changethe wavelength of light emitted from the light emitting device 520. Thelight emitting device packages may include at least one of lightemitting devices according to the afore-mentioned embodiments, but thedisclosure is not limited thereto.

An array of plural light emitting device packages in accordance withthis embodiment may be mounted on a substrate, and optical members, suchas a light guide panel, a prism sheet, a diffusion sheet, etc., may bedisposed on an optical path of the light emitting device packages. Thelight emitting device packages, the substrate and the optical membersmay function as a backlight unit.

In accordance with other embodiments, the light emitting devices or thelight emitting device package in accordance with the above-describedembodiments may constitute a display apparatus, an indicating apparatusand a lighting system, and, for example, the lighting system may includea lamp or a streetlight.

FIG. 12 is an exploded perspective view of a lighting apparatusincluding light emitting device packages in accordance with oneembodiment. With reference to FIG. 12, the lighting apparatus inaccordance with this embodiment includes a light source 750 to projectlight, a housing 700 in which the light source 750 is installed, a heatdissipation unit 740 to dissipate heat generated by the light source750, and a holder 760 to couple the light source 750 and the heatdissipation unit 740 to the housing 700.

The housing 700 includes a socket connector 710 coupled to an electricalsocket (not shown) and a body 730 connected to the socket connector 710and accommodating the light source 750. One air flow hole 720 may beformed through the body 730.

A plurality of air flow holes 720 may be provided on the body 730 of thehousing 700. One air flow hole 720 may be formed, or plural air flowholes 720 may be arranged in a radial shape or various other shapes.

The light source 750 includes a plurality of light emitting devicepackages 752 provided on a substrate 754. Here, the substrate 754 mayhave a shape which is capable of being inserted into an opening of thehousing 700, and be formed of a material having high thermalconductivity so as to transfer heat to the heat dissipation unit 740, asdescribed later. The plurality of light emitting device package may bethe light emitting device package according to the aforementionedembodiments.

The holder 760 is provided under the light source 750. The holder 760may include a frame and air flow holes. Further, although not shown inFIG. 12, optical members may be provided under the light source 750 soas to diffuse, scatter or converge light projected from the lightemitting device packages 752 of the light source 750.

FIG. 13 is an exploded perspective view of a display apparatus 800including light emitting device packages according to one embodiment.

Referring to FIG. 13, the display apparatus 800 includes a bottom cover810, a reflective plate 820 disposed on the bottom cover 810, lightemitting modules 830 and 835 to emit light, a light guide plate 840disposed on the front surface of the reflective plate 820 to guide lightemitted from the light emitting modules 830 and 835 to the front part ofthe display device, an optical sheet including prism sheets 850 and 860disposed on the front surface of the light guide plate 840, a displaypanel 870 disposed on the front surface of the optical sheet, an imagesignal output circuit 872 connected to the display panel 870 to supplyan image signal to the display panel 870, and a color filter 880disposed on the front surface of the display panel 870. Here, the bottomcover 810, the reflective plate 820, the light emitting modules 830 and835, the light guide plate 840, and the optical sheet may constitute abacklight unit.

The light emitting modules may include a light emitting device package835 on the substrate 830. Here, the substrate 830 may be formed of PCBor the like. The light emitting device package 835 may be the lightemitting device package according to the afore-mentioned embodiment.

The bottom cover 810 may accommodate components within the image displayapparatus 800. The reflective plate 820 may be provided as a separatecomponent, as shown in FIG. 13, or be provided by coating the rearsurface of the light guide plate 840 or the front surface of the bottomcover 810 with a material having high reflectivity.

The reflective plate 820 may be formed of a material that has highreflectivity and may be useful in an ultra-thin form, such aspolyethylene terephthalate (PET).

The light guide plate 840 is formed of a material such aspolymethylmethacrylate (PMMA), polycarbonate (PC) or polyethylene (PE).

The first prism sheet 850 is formed of a light transmitting and elasticpolymer on one surface of a support film, and the polymer may have aprism layer in which plural three-dimensional structures are repeated.Here, such plural patterns may be formed in a strip manner in whichridges and valleys are repeated, as shown in the drawing.

A direction of ridges and valleys formed on one surface of a supportfilm of the second prism sheet 860 may be perpendicular to a directionof the ridges and the valleys formed on one surface of the support filmof the first prism sheet 850. This serves to uniformly distribute lighttransmitted from the light source module and the reflective plate 820 inall directions of the panel 870.

Although not shown, a diffusion sheet may be disposed between the lightguide plate 840 and the first prism sheet 850. The diffusion sheet maybe made of polyester and polycarbonate and maximizes transmission angleof light emitted from the backlight unit through refraction andscattering. Also, the diffusion sheet may include a support layerincluding a light diffusion agent, and a first layer and a second layerthat are formed on a light emission surface (first prism sheetdirection) and a light incident surface (reflective sheet direction) anddo not include a light diffusion agent.

In this embodiment, although optical sheets include the diffusion sheet,the first prism sheet 850 and the second prism sheet 860, the opticalsheets may include another combination, for example, a micro lens array,a combination of the diffusion sheet and the micro lens array, or acombination of one prism sheet and the micro lens array.

As the display panel 870, a liquid crystal display panel may beprovided, or other kinds of display apparatuses requiring a light sourcemay be provided instead of the liquid crystal display panel.

As is apparent from the above description, the light emitting deviceaccording to the embodiments has improved reliability and efficiency andenables control an area of light emitting regions according to theintended purpose, thus increasing a light emitting area, dispersingcurrent and improving light emission efficiency.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

What is claimed is:
 1. A light emitting device comprising: a lightemitting structure comprising a plurality of light emitting regionscomprising a first semiconductor layer, an active layer and a secondsemiconductor layer; a first electrode unit disposed on the firstsemiconductor layer in one of the light emitting regions; a secondelectrode unit disposed on the second semiconductor layer in another ofthe light emitting regions; an intermediate pad disposed on the first orsecond semiconductor layer in at least still another of the lightemitting regions; and at least one connection electrode to sequentiallyconnect the light emitting regions in series, wherein the light emittingregions connected in series are divided into 1^(st) to i^(th) lightemitting region groups and areas of light emitting regions that belongto different groups are different (where 1<j≦j, each of i and j is anatural number, and j is a last light emitting region group).
 2. Thelight emitting device according to claim 1, wherein areas of lightemitting regions that belong to the same group are identical.
 3. Thelight emitting device according to claim 1, wherein at least one of atransverse length and a longitudinal length of light emitting regionsthat belong to different groups are different.
 4. The light emittingdevice according to claim 1, wherein an area of a light emitting regionthat belongs to an i−1^(th) group is larger than an area of a lightemitting region that belongs to an i^(th) group.
 5. The light emittingdevice according to claim 1, wherein areas of light emitting regionsthat belong to respective groups decrease from the 1^(st) group to thej^(th) group in order.
 6. The light emitting device according to claim1, wherein the intermediate pad is disposed on the second semiconductorlayer or the first semiconductor layer in the last light emitting regionamong light emitting regions that belong to at least one of groups otherthan the j^(th) group.
 7. The light emitting device according to claim1, wherein the intermediate pad is electrically connected to theconnection electrode in the same light emitting region.
 8. The lightemitting device according to claim 1, further comprising: an insulatinglayer disposed in the light emitting regions, wherein the connectionelectrode is disposed on the insulating layer.
 9. The light emittingdevice according to claim 8, wherein the connection electrode comprises:a first portion that passes through the insulating layer and contactsthe first semiconductor layer in one of adjacent light emitting regions;and a second portion that passes through the insulating layer, thesecond semiconductor layer and the active layer, and contacts the secondsemiconductor layer in the other of the adjacent light emitting regions,wherein the insulating layer is disposed between the second portion andthe second semiconductor layer, and between the second portion and theactive layer.
 10. A light emitting device comprising: a light emittingstructure comprising a plurality of light emitting regions comprising afirst semiconductor layer, an active layer and a second semiconductorlayer; a plurality of metal layers disposed under the secondsemiconductor layers in the respective light emitting regions; a firstelectrode unit disposed on the first semiconductor layer in one of thelight emitting regions; a second electrode unit electrically connectedto the metal layer disposed under the second semiconductor layer inanother of the light emitting regions; an intermediate pad disposed onthe first semiconductor layer in at least still another of the lightemitting regions; and an insulating layer to electrically insulate themetal layers from each other, wherein the light emitting regionsconnected in series are divided into 1^(st) to i^(th) light emittingregion groups and areas of light emitting regions that belong todifferent groups are different (where 1<i≦j, each of i and j is anatural number, and j is a last light emitting region group).
 11. Thelight emitting device according to claim 10, wherein the secondelectrode unit is connected to the metal layer in the first lightemitting region among light emitting regions that belong to the 1^(st)group.
 12. The light emitting device according to claim 10, whereinareas of light emitting regions that belong to the same group areidentical.
 13. The light emitting device according to claim 10, whereinan area of a light emitting region that belongs to an i−1^(th) group islarger than an area of a light emitting region that belongs to an i^(th)group.
 14. The light emitting device according to claim 10, whereinareas of light emitting regions that belong to respective groupsdecrease from the 1^(st) group to the j^(th) group in order.
 15. Thelight emitting device according to claim 10, wherein the intermediatepad is disposed on the first semiconductor layer in the last lightemitting region among light emitting regions that belong to at least oneof groups other than the j^(th) group.
 16. The light emitting deviceaccording to claim 10, wherein each metal layer comprises at least oneof an ohmic layer and a reflective layer.
 17. The light emitting deviceaccording to claim 10, further comprising: a passivation layer disposedin the light emitting regions, wherein the connection electrode isdisposed on the passivation layer.
 18. The light emitting deviceaccording to claim 10, wherein the second electrode unit comprises: abarrier layer electrically connected to the metal layer disposed inanother of the light emitting regions; and a support layer disposedunder the barrier layer.
 19. The light emitting device according toclaim 17, wherein the connection electrode comprises: at least one firstportion that passes through the passivation layer, the firstsemiconductor layer and the active layer, and contacts the secondsemiconductor layer in one of adjacent light emitting regions; and atleast one second portion that passes through the passivation layer andcontacts the first semiconductor layer in the other of the adjacentlight emitting regions, wherein the passivation layer is disposedbetween the first portion and the first semiconductor layer, and betweenthe first portion and the active layer.
 20. The light emitting deviceaccording to claim 10, wherein the insulating layer electricallyinsulates metal layers other than the metal layer electrically connectedto the second electrode unit, from the second electrode unit.